Re: statm_pgd_range() sucks!

[Andrew Morton]

William Lee Irwin III wrote:
> 
> William Lee Irwin III wrote:
> >> (1) shared, lib, text, & total are now reported as what's mapped
> >>         instead of what's resident. This actually fixes two bugs:
> 
> On Thu, Aug 29, 2002 at 07:51:44PM -0700, Andrew Morton wrote:
> > hmm.  Personally, I've never believed, or even bothered to try to
> > understand what those columns are measuring.  Does anyone actually
> > find them useful for anything?  If so, what are they being used for?
> > What info do we really, actually want to know?
> 
> I'm basically looking for VSZ, RSS, %cpu, & pid -- after that I don't
> care.

Well statistics coming out of the kernel can be quite vital in the tuning
of real world applications - they're not just for kernel developers.  The
stats contribute to the bottom-line performance and stability of the things
for which people are actually using the kernel.  That's a motherhood statement,
I know, but I think it's important.

> ...
> 
> Per-vma RSS is trivial, just less self-contained. Everywhere the
> mm->rss is touched, the vma to account that to is also known, except
> for put_dirty_page(), and that can be repaired as its caller knows.

This would provide useful information at a justifiable cost, don't you
think?

(ho-hum, all right.  I'll code it ;))